The following makes sure the emitted even/odd extraction scheme
follows one that ends up with actual trivial even/odd extract permutes.
When we choose a level 2 extract we generate { 0, 1, 4, 5, ... }
which for example the x86 backend doesn't recognize with just SSE
and QImode elements. So this now follows what the non-SLP interleaving
code would do which is element granular even/odd extracts.
This resolves gcc.dg/vect/vect-strided[-a]-u8-i8-gap*.c FAILs with
--param vect-force-slp=1 on x86_64.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
* tree-vect-slp.cc (vect_lower_load_permutations): Prefer
level 1 even/odd extracts.
---
gcc/tree-vect-slp.cc | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 482b9d50496..2274d0e428e 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -4426,25 +4426,28 @@ vect_lower_load_permutations (loop_vec_info loop_vinfo,
/* Now build an even or odd extraction from the unpermuted load. */
lane_permutation_t perm;
perm.create ((group_lanes + 1) / 2);
- unsigned level;
- if (even
- && ((level = 1 << ctz_hwi (even)), true)
- && group_lanes % (2 * level) == 0)
+ unsigned even_level = even ? 1 << ctz_hwi (even) : 0;
+ unsigned odd_level = odd ? 1 << ctz_hwi (odd) : 0;
+ if (even_level
+ && group_lanes % (2 * even_level) == 0
+ /* ??? When code generating permutes we do not try to pun
+ to larger component modes so level != 1 isn't a natural
+ even/odd extract. Prefer one if possible. */
+ && (even_level == 1 || !odd_level || odd_level != 1))
{
/* { 0, 1, ... 4, 5 ..., } */
- unsigned level = 1 << ctz_hwi (even);
- for (unsigned i = 0; i < group_lanes / 2 / level; ++i)
- for (unsigned j = 0; j < level; ++j)
- perm.quick_push (std::make_pair (0, 2 * i * level + j));
+ for (unsigned i = 0; i < group_lanes / 2 / even_level; ++i)
+ for (unsigned j = 0; j < even_level; ++j)
+ perm.quick_push (std::make_pair (0, 2 * i * even_level + j));
}
- else if (odd)
+ else if (odd_level)
{
/* { ..., 2, 3, ... 6, 7 } */
- unsigned level = 1 << ctz_hwi (odd);
- gcc_assert (group_lanes % (2 * level) == 0);
- for (unsigned i = 0; i < group_lanes / 2 / level; ++i)
- for (unsigned j = 0; j < level; ++j)
- perm.quick_push (std::make_pair (0, (2 * i + 1) * level + j));
+ gcc_assert (group_lanes % (2 * odd_level) == 0);
+ for (unsigned i = 0; i < group_lanes / 2 / odd_level; ++i)
+ for (unsigned j = 0; j < odd_level; ++j)
+ perm.quick_push
+ (std::make_pair (0, (2 * i + 1) * odd_level + j));
}
else
{
--
2.43.0
